use clap::{Parser, Subcommand};
use std::path::PathBuf;
use umya_spreadsheet::*;
use std::fs;
use std::io::Write;
use chrono::{NaiveDate, NaiveDateTime, NaiveTime};

// --- 日期时间辅助逻辑 (新增) ---

/// 尝试将字符串解析为日期时间，并返回对应的 Excel 格式代码
fn try_parse_datetime(s: &str) -> Option<(NaiveDateTime, &'static str)> {
    const FORMATS: &[(&str, &str)] = &[
        ("%Y-%m-%d %H:%M:%S", "yyyy-mm-dd hh:mm:ss"),
        ("%Y/%m/%d %H:%M:%S", "yyyy/mm/dd hh:mm:ss"),
        ("%Y-%m-%d", "yyyy-mm-dd"),
        ("%Y/%m/%d", "yyyy/mm/dd"),
        ("%H:%M:%S", "hh:mm:ss"),
        ("%H:%M", "hh:mm"),
    ];

    for (fmt_str, excel_fmt) in FORMATS {
        // 1. 尝试解析为完整 DateTime
        if let Ok(dt) = NaiveDateTime::parse_from_str(s, fmt_str) {
            return Some((dt, excel_fmt));
        }
        // 2. 尝试解析为 Date (默认时间 00:00:00)
        if let Ok(d) = NaiveDate::parse_from_str(s, fmt_str) {
            let dt = d.and_hms_opt(0, 0, 0).unwrap();
            return Some((dt, excel_fmt));
        }
        // 3. 尝试解析为 Time (默认日期 1899-12-30，Excel 纪元)
        if let Ok(t) = NaiveTime::parse_from_str(s, fmt_str) {
            let dt = NaiveDate::from_ymd_opt(1899, 12, 30).unwrap().and_time(t);
            return Some((dt, excel_fmt));
        }
    }
    None
}

/// 将 Chrono 时间转换为 Excel 序列号 (f64)
fn datetime_to_excel_serial(dt: &NaiveDateTime) -> f64 {
    // Excel 的 Windows 纪元是 1899-12-30 (由于历史 Bug)
    let excel_epoch = NaiveDate::from_ymd_opt(1899, 12, 30)
        .unwrap()
        .and_hms_opt(0, 0, 0)
        .unwrap();
    
    let duration = dt.signed_duration_since(excel_epoch);
    let days = duration.num_days() as f64;
    let secs = (duration.num_seconds() % 86400).abs() as f64;
    
    days + (secs / 86400.0)
}

/// 将 Excel 序列号转换回 Chrono 时间
fn excel_serial_to_datetime(serial: f64) -> Option<NaiveDateTime> {
    let excel_epoch = NaiveDate::from_ymd_opt(1899, 12, 30)
        .unwrap()
        .and_hms_opt(0, 0, 0)
        .unwrap();
    
    let days = serial.trunc() as i64;
    let fraction = serial.fract().abs();
    let secs = (fraction * 86400.0).round() as i64;

    excel_epoch
        .checked_add_signed(chrono::Duration::days(days))?
        .checked_add_signed(chrono::Duration::seconds(secs))
}

// --- 错误处理 (原有) ---

#[derive(Debug, thiserror::Error)]
enum DexcelError {
    #[error("IO错误: {0}")]
    Io(#[from] std::io::Error),
    #[error("Excel错误: {0}")]
    Umya(String),
    #[error("操作错误: {0}")]
    Operation(String),
}

type Result<T> = std::result::Result<T, DexcelError>;

// --- CLI 定义 (原有，未改动) ---

#[derive(Parser)]
#[command(name = "dexcel")]
#[command(about = "Excel 读写工具 (样式保留版)", long_about = None)]
struct Cli {
    /// Excel 文件路径
    #[arg(required_if_eq("command", "query"))]
    #[arg(required_if_eq("command", "count"))]
    #[arg(required_if_eq("command", "insert"))]
    #[arg(required_if_eq("command", "update"))]
    #[arg(required_if_eq("command", "delete"))]
    #[arg(required_if_eq("command", "style"))]
    file: Option<PathBuf>,

    #[command(subcommand)]
    command: Commands,
}

#[derive(Subcommand)]
enum Commands {
    /// 查询数据 (只读)
    Query {
        #[arg(default_value_t = 0, allow_hyphen_values = true)]
        count: i32,
        #[arg(long, allow_hyphen_values = true)]
        start: Option<i32>,
        #[arg(long)]
        last: bool,
        #[arg(long)]
        sheet: Option<String>,
    },
    /// 统计行数
    Count {
        #[arg(long)]
        sheet: Option<String>,
    },
    /// 创建新文件
    New {
        name: String,
        #[arg(long)]
        sheet: Option<String>,
    },
    /// 插入行 (保留样式)
    Insert {
        /// 要插入的值 (用 | 分隔)
        value: String,
        /// 插入位置 (空则追加)
        #[arg(long, allow_hyphen_values = true)]
        row: Option<i32>,
        #[arg(long)]
        sheet: Option<String>,
        #[arg(long, default_value = "|")]
        split: String,
    },
    /// 更新数据 (保留样式)
    Update {
        /// 新值
        value: String,
        /// 行号
        #[arg(long, allow_hyphen_values = true)]
        row: i32,
        /// 起始列号 (默认1)
        #[arg(long)]
        cell: Option<u32>,
        #[arg(long)]
        sheet: Option<String>,
        #[arg(long, default_value = "|")]
        split: String,
    },
    /// 删除行
    Delete {
        /// 起始行号（支持负数）
        #[arg(allow_hyphen_values = true)]
        start: i32,
        /// 删除的行数（默认1）
        #[arg(long, default_value_t = 1)]
        count: u32,
        /// 跳过确认
        #[arg(long, short = 'y')]
        yes: bool,
        #[arg(long)]
        sheet: Option<String>,
    },
    /// 设置样式
    Style {
        #[arg(long, allow_hyphen_values = true)]
        rows: Vec<i32>,
        #[arg(long)]
        cols: Vec<u32>,
        #[arg(long)]
        row_height: Option<f64>,
        #[arg(long)]
        col_width: Option<f64>,
        #[arg(long)]
        wrap_text: bool,
        #[arg(long)]
        sheet: Option<String>,
    },
}

// --- 核心工具函数 (原有 + 修改 get_cell_value) ---

// 安全保存辅助
fn safe_save_umya(book: &mut Spreadsheet, target: &PathBuf) -> Result<()> {
    let backup = if target.exists() {
        let backup = target.with_extension("xlsx.bak");
        let _ = fs::remove_file(&backup);
        fs::copy(target, &backup)?;
        Some(backup)
    } else {
        None
    };
    
    // 尝试写入文件
    match writer::xlsx::write(book, target) {
        Ok(_) => {
            // 写入成功，删除备份文件
            if let Some(bak) = backup {
                let _ = fs::remove_file(bak);
            }
            Ok(())
        }
        Err(e) => {
            // 写入失败，恢复备份
            if let Some(bak) = &backup {
                if bak.exists() {
                    let _ = fs::copy(bak, target);
                }
            }
            Err(DexcelError::Umya(e.to_string()))
        }
    }
}

fn get_sheet_mut<'a>(book: &'a mut Spreadsheet, name: &Option<String>) -> Result<&'a mut Worksheet> {
    match name {
        Some(n) => book.get_sheet_by_name_mut(n).ok_or_else(|| DexcelError::Operation(format!("找不到Sheet: {}", n))),
        None => Ok(book.get_sheet_mut(&0).ok_or_else(|| DexcelError::Operation("找不到Sheet".to_string()))?),
    }
}

fn get_sheet<'a>(book: &'a Spreadsheet, name: &Option<String>) -> Result<&'a Worksheet> {
    match name {
        Some(n) => book.get_sheet_by_name(n).ok_or_else(|| DexcelError::Operation(format!("找不到Sheet: {}", n))),
        None => Ok(book.get_sheet(&0).ok_or_else(|| DexcelError::Operation("找不到Sheet".to_string()))?),
    }
}

// 解析行号 (1-based -> 0-based)
fn resolve_row(input: i32, max: usize) -> Result<usize> {
    let max_i = max as i32;
    let idx = if input < 0 { max_i + input } else { input - 1 };
    
    if idx < 0 || idx >= max_i {
        Err(DexcelError::Operation(format!("行号 {} 超出范围", input)))
    } else {
        Ok(idx as usize)
    }
}

// --- 修改版：获取单元格值 (支持日期格式化显示) ---
fn get_cell_value(sheet: &Worksheet, row: usize, col: usize) -> String {
    // 坐标是 (col, row) 1-based
    let coord = (col as u32 + 1, row as u32 + 1);
    
    if let Some(c) = sheet.get_cell(coord) {
        let value = c.get_value();
        
        // 尝试判断是否为日期格式的数字
        if let Some(serial) = c.get_value_number() {
            if let Some(num_fmt) = c.get_style().get_number_format() {
                let fmt_code = num_fmt.get_format_code();
                
                // 简单 heuristic：如果格式码包含日期关键字，尝试转换
                let is_date_like = fmt_code.contains("yyyy") || fmt_code.contains("mm") || fmt_code.contains("dd") || 
                                   fmt_code.contains("hh") || fmt_code.contains("ss");

                if is_date_like {
                    if let Some(dt) = excel_serial_to_datetime(serial) {
                        // 根据 Excel 格式的类型返回不同的 Rust 格式
                        if fmt_code.contains("yyyy") && fmt_code.contains("hh") {
                            return dt.format("%Y-%m-%d %H:%M:%S").to_string();
                        } else if fmt_code.contains("yyyy") {
                            return dt.format("%Y-%m-%d").to_string();
                        } else if fmt_code.contains("hh") && fmt_code.contains("ss") {
                            return dt.format("%H:%M:%S").to_string();
                        } else if fmt_code.contains("hh") {
                            return dt.format("%H:%M").to_string();
                        }
                    }
                }
            }
        }
        
        // 默认返回
        value.to_string()
    } else {
        String::new()
    }
}

// --- Main 入口 (原有，未改动) ---

fn main() -> Result<()> {
    let cli = Cli::parse();
    let result = match &cli.command {
        Commands::Query { count, start, last, sheet } => {
            let file = cli.file.as_ref().unwrap();
            let book = reader::xlsx::read(file).map_err(|e| DexcelError::Umya(e.to_string()))?;
            query_excel(&book, *count, *start, *last, sheet)
        }
        Commands::Count { sheet } => {
            let file = cli.file.as_ref().unwrap();
            let book = reader::xlsx::read(file).map_err(|e| DexcelError::Umya(e.to_string()))?;
            count_excel(&book, sheet)
        }
        Commands::New { name, sheet } => {
            let path = if name.ends_with(".xlsx") { PathBuf::from(name) } else { PathBuf::from(format!("{}.xlsx", name)) };
            let mut book = new_file();
            if let Some(s) = sheet {
                book.get_sheet_mut(&0).unwrap().set_name(s);
            }
            writer::xlsx::write(&book, &path).map_err(|e| DexcelError::Umya(e.to_string()))?;
            println!("✓ 已创建: {}", path.display());
            Ok(())
        }
        Commands::Insert { value, row, sheet, split } => {
            let file = cli.file.as_ref().unwrap();
            let mut book = reader::xlsx::read(file).map_err(|e| DexcelError::Umya(e.to_string()))?;
            insert_excel(&mut book, value, *row, sheet, split)?;
            safe_save_umya(&mut book, file)
        }
        Commands::Update { value, row, cell, sheet, split } => {
            let file = cli.file.as_ref().unwrap();
            let mut book = reader::xlsx::read(file).map_err(|e| DexcelError::Umya(e.to_string()))?;
            update_excel(&mut book, value, *row, *cell, sheet, split)?;
            safe_save_umya(&mut book, file)
        }
        Commands::Delete { start, count, yes, sheet } => {
            let file = cli.file.as_ref().unwrap();
            let mut book = reader::xlsx::read(file).map_err(|e| DexcelError::Umya(e.to_string()))?;
            delete_excel(&mut book, *start, *count, *yes, sheet)?;
            safe_save_umya(&mut book, file)
        }
        Commands::Style { rows, cols, row_height, col_width, wrap_text, sheet } => {
            let file = cli.file.as_ref().unwrap();
            let mut book = reader::xlsx::read(file).map_err(|e| DexcelError::Umya(e.to_string()))?;
            style_excel(&mut book, rows, cols, *row_height, *col_width, *wrap_text, sheet)?;
            safe_save_umya(&mut book, file)
        }
    };

    if let Err(e) = result {
        eprintln!("❌ 错误: {}", e);
        std::process::exit(1);
    }
    
    Ok(())
}

// --- 具体实现 (修改了 Insert 和 Update 的写入逻辑) ---

fn query_excel(book: &Spreadsheet, count: i32, start: Option<i32>, last: bool, sheet_name: &Option<String>) -> Result<()> {
    let sheet = get_sheet(book, sheet_name)?;
    let (_, max_row) = sheet.get_highest_column_and_row(); // 注意：umya 返回 (col, row)
    let total_rows = max_row as usize;

    if total_rows == 0 {
        println!("表格为空");
        return Ok(());
    }

    // 计算范围逻辑
    let (start_row, end_row) = if last {
        (total_rows - 1, total_rows)
    } else if let Some(s) = start {
        let actual_start = if s < 0 {
            let pos = total_rows as i32 + s;
            if pos < 0 { 0 } else { pos as usize }
        } else {
            (s as usize).saturating_sub(1)
        };
        
        if count > 0 {
            (actual_start, (actual_start + count as usize).min(total_rows))
        } else if count < 0 {
            (actual_start, (actual_start + (-count) as usize).min(total_rows))
        } else {
            let max = 20;
            (actual_start, (actual_start + max).min(total_rows))
        }
    } else if count > 0 {
        (0, count as usize)
    } else if count < 0 {
        let abs = (-count) as usize;
        let start = if abs >= total_rows { 0 } else { total_rows - abs };
        (start, total_rows)
    } else {
        let max = 20;
        ((total_rows - max).max(0), total_rows)
    };

    let (max_col, _) = sheet.get_highest_column_and_row();
    
    use tabled::builder::Builder;
    let mut builder = Builder::default();
    
    for r in start_row..end_row.min(total_rows) {
        let row: Vec<String> = (0..max_col as usize)
            .map(|c| get_cell_value(sheet, r, c))
            .collect();
        builder.push_record(row);
    }

    let mut table = builder.build();
    table.with(tabled::settings::Style::modern());
    println!("{}", table);

    Ok(())
}

fn count_excel(book: &Spreadsheet, sheet_name: &Option<String>) -> Result<()> {
    let sheet = get_sheet(book, sheet_name)?;
    let (_, row) = sheet.get_highest_column_and_row();
    println!("{}", row);
    Ok(())
}

// --- 修改版：插入行 (支持日期写入) ---
fn insert_excel(
    book: &mut Spreadsheet,
    value: &str,
    row: Option<i32>,
    sheet_name: &Option<String>,
    split: &str,
) -> Result<()> {
    let sheet = get_sheet_mut(book, sheet_name)?;
    let (_, max_row) = sheet.get_highest_column_and_row();
    
    // 确定插入位置 (umya 是 1-based)
    let insert_idx_1based = match row {
        Some(r) => {
            if r < 0 {
                (max_row as i32 + r + 2).max(1) as u32
            } else {
                r.max(1) as u32
            }
        }
        None => max_row + 1,
    };

    if insert_idx_1based <= max_row {
        sheet.insert_new_row(&insert_idx_1based, &1);
    }

    // 写入数据 (逻辑增强)
    let vals: Vec<&str> = value.split(split).collect();
    for (i, val) in vals.iter().enumerate() {
        let col = (i + 1) as u32;
        let cell = sheet.get_cell_mut((col, insert_idx_1based));
        let val_trimmed = val.trim();
        
        if !val_trimmed.is_empty() {
            // 1. 尝试解析日期
            if let Some((dt, excel_fmt)) = try_parse_datetime(val_trimmed) {
                let serial = datetime_to_excel_serial(&dt);
                cell.set_value_number(serial);
                // 关键：设置单元格格式，这样 Excel 才会把它当日期看
                cell.get_style_mut().get_number_format_mut().set_format_code(excel_fmt);
            } else {
                // 2. 写入文本
                cell.set_value(val_trimmed);
            }
        }
    }

    println!("✓ 已在第 {} 行插入数据 (样式已保留)", insert_idx_1based);
    Ok(())
}

// --- 修改版：更新行 (支持日期写入) ---
fn update_excel(
    book: &mut Spreadsheet,
    value: &str,
    row: i32,
    cell: Option<u32>,
    sheet_name: &Option<String>,
    split: &str,
) -> Result<()> {
    let sheet = get_sheet_mut(book, sheet_name)?;
    let (_, max_row) = sheet.get_highest_column_and_row();
    
    let target_row = resolve_row(row, max_row as usize)? as u32 + 1; // 转为 1-based
    let start_col = cell.unwrap_or(1);

    let vals: Vec<&str> = value.split(split).collect();
    
    for (i, val) in vals.iter().enumerate() {
        let c = start_col + i as u32;
        let cell_obj = sheet.get_cell_mut((c, target_row));
        let val_trimmed = val.trim();
        
        if !val_trimmed.is_empty() {
            // 1. 尝试解析日期
            if let Some((dt, excel_fmt)) = try_parse_datetime(val_trimmed) {
                let serial = datetime_to_excel_serial(&dt);
                cell_obj.set_value_number(serial);
                cell_obj.get_style_mut().get_number_format_mut().set_format_code(excel_fmt);
            } else {
                // 2. 写入文本
                cell_obj.set_value(val_trimmed);
            }
        }
    }

    println!("✓ 已更新第 {} 行 (样式未改变)", row);
    Ok(())
}

fn delete_excel(
    book: &mut Spreadsheet,
    start: i32,
    count: u32,
    yes: bool,
    sheet_name: &Option<String>,
) -> Result<()> {
    let sheet = get_sheet_mut(book, sheet_name)?;
    let (_, max_row) = sheet.get_highest_column_and_row();

    // 解析起始行 (转为 1-based)
    let start_del = if start < 0 {
        // 负数：从后往前数
        let pos = (max_row as i32 + start + 1).max(1) as u32;
        pos
    } else {
        // 正数：直接使用
        start.max(1) as u32
    };

    let end_del = (start_del + count - 1).min(max_row);

    // 确认
    if !yes {
        eprintln!("⚠ 即将删除第 {} 至 {} 行（共 {} 行）", start_del, end_del, count);
        eprint!("确认? (y/N): ");
        std::io::stdout().flush()?;
        let mut input = String::new();
        std::io::stdin().read_line(&mut input)?;
        if !input.trim().eq_ignore_ascii_case("y") {
            println!("操作已取消");
            return Ok(());
        }
    }

    // 调用 umya 的删除方法
    sheet.remove_row(&start_del, &count);

    println!("✓ 已删除第 {} 至 {} 行（共 {} 行）", start_del, end_del, count);
    Ok(())
}

fn style_excel(
    book: &mut Spreadsheet,
    rows: &[i32],
    cols: &[u32],
    row_height: Option<f64>,
    col_width: Option<f64>,
    wrap_text: bool,
    sheet_name: &Option<String>,
) -> Result<()> {
    let sheet = get_sheet_mut(book, sheet_name)?;
    let (_, max_row) = sheet.get_highest_column_and_row();
    let (max_col, _) = sheet.get_highest_column_and_row();

    let target_rows: Vec<u32> = if rows.is_empty() {
        (1..=max_row).collect()
    } else {
        rows.iter().filter_map(|&r| resolve_row(r, max_row as usize).ok()).map(|x| x as u32 + 1).collect()
    };

    let target_cols: Vec<u32> = if cols.is_empty() {
        (1..=max_col).collect()
    } else {
        cols.to_vec()
    };

    for &r in &target_rows {
        if let Some(h) = row_height {
            let row = sheet.get_row_dimension_mut(&r);
            row.set_height(h);
        }
    }
    
    for &c in &target_cols {
        if let Some(w) = col_width {
            let col = sheet.get_column_dimension_by_number_mut(&c);
            col.set_width(w);
        }
    }

    if wrap_text {
        use umya_spreadsheet::structs::HorizontalAlignmentValues;
        for r in &target_rows {
            for c in &target_cols {
                let cell = sheet.get_cell_mut((*c, *r));
                let mut align = cell.get_style().get_alignment().cloned().unwrap_or_default();
                align.set_horizontal(HorizontalAlignmentValues::Left);
                align.set_wrap_text(true);
                cell.get_style_mut().set_alignment(align);
            }
        }
    }

    println!("✓ 样式应用成功");
    Ok(())
}